While giving evidence to a Parliamentary Committee he hinted at a change of heart towards the £1bn project to harness tidal power in the Bristol Channel.

Presently project boss Andrew McNaughton is trying to negotiate a strike price for electricity generated from the scheme with Government, but talks are deadlocked over the high price being asked for.

Already construction of the project has been delayed by a year, and the project team has been cut-back, as subsidy discussions with the UK Government continue.

During evidence to Parliament’s Liason Committee, David Cameron said: “Instinctively, I can see the strength of the argument for tidal power, because one of the problems with renewables is whether they can provide base-load power.

“Nuclear can. Wind cannot, because it is intermittent. But tidal, because the tide is always going in or out, can provide base-load power.

“The problem with tidal power, simply put, is that at the moment we have not seen any ideas come forward that can hit a strike price in terms of pounds per megawatt-hour that is very attractive.

“That is the challenge for tidal. Maybe they can come up with something. They are very long-term schemes with big investments up front, and they can last for many, many years, but right now my enthusiasm is reduced slightly by the fact that the cost would be quite high.”